(CNN) -- At least 23 people were killed and dozens wounded in a series of attacks targeting Sunni areas across northern Iraq on Thursday, police officials told CNN.
The deadliest attack was in Samarra, where 16 people died when a car bomb exploded in an outdoor market Thursday evening. Another 27 were wounded in the largely Sunni city, about 100 km (63 miles) north of Baghdad, police said.
In Baghdad, gunmen shot dead three men outside their house in Saydiya, a mixed Sunni-Shiite area on the city's southwest side. And in al-Adil, a Sunni neighborhood in western Baghdad, gunmen opened fire on a group of people in a residential area and killed two people, police said.
In Mosul, a car bomb exploded outside a local hospital and killed two people. Nine other people were wounded in this explosion. Mosul is a largely Sunni city about 360 km (224 miles) north of Baghdad.
Police officials in those cities spoke on condition of anonymity because they are not allowed to release information to media.
The latest bloodshed followed the deaths of 56 people Wednesday in a series of blasts that targeted mostly Shiite areas in and around Baghdad. Another 200 were wounded.
The country has endured months of escalating violence stemming from decades-old discord between the nation's Sunnis and Shiites, the two largest branches of Islam. July was the deadliest month in Iraq since the peak of sectarian violence in 2006 and 2007. According to the United Nations, 1,057 Iraqis were killed and another 2,326 were wounded in acts of terrorism and violence last month.
Sunnis have felt politically marginalized under a Shiite-led government since the ouster of longtime leader Saddam Hussein in the 2003 U.S.-led invasion. Meanwhile, the government is wary that the Sunni Islamists who've been involved in fighting Syrian President Bashar al-Assad's government are now targeting the government in Baghdad.
Sunni-Shiites frictions have escalated since an April incident in Hawija, in northern Iraq, where Iraqi security forces raided a site used by Sunni protesters to demonstrate against the Shiite-led government. Sunni protests against the Iraqi government have continued since the Hawija incident.